聚氨酯加固南海钙质砂静力特性试验研究

Experimental Study on Static Characteristics of Reinforced Calcareous Sand in South China Sea by Polyurethane

为评价聚氨酯泡沫胶黏剂对钙质砂的加固效果,通过单轴压缩试验和三轴剪切试验,研究了聚氨酯对钙质砂强度和变形特性的影响;并采用Duncan-Chang模型对三轴试验结果进行拟合,分析了聚氨酯胶凝钙质砂的变形及应力规律。结果表明:将聚氨酯掺入到钙质砂中可以稳定地提高钙质砂的承载能力,且增加掺量可提高固化效果;聚氨酯的掺入,不仅提高钙质砂的抗剪强度,而且减少了相同应力条件下钙质砂地基的沉降量;聚氨酯填充砂颗粒间的孔隙,使松散的钙质砂形成不规则的连续体或不连续体,增强了钙质砂的整体性,从而达到提高强度的目的。

To evaluate the reinforcement effect of polyurethane foam adhesive on calcareous sand, the effect of polyurethane on the strength and deformation characteristics of calcareous sand were studied in uniaxial compression test and triaxial shear test. In addition, the Duncan-Chang model was used to fit the triaxial test results, and the deformation and stress distribution of polyurethane cemented calcareous sand were analyzed. Results show that the loading capacity of calcareous sand can be steadily enhanced by adding polyurethane into calcareous sand, and the curing effect can be improved by increasing the content of polyurethane. The addition of polyurethane not only improve the shear resistance of calcareous sand, but also reduce the settlement of calcareous sand foundation under the same stress conditions. Polyurethane filling into pores among sand particles, glued the loose calcareous sand into irregular continue or discontinue masses, which greatly enhanced the integrity of calcareous sand, thus the strength of modified materials were improved.